Interaction of\nNitric Oxide with Late 3d Transition\nMetals: Dissociation and Metal Oxidation

Heterogeneous interfaces influence chemical reactions\nby stabilizing\nthe adsorption of reactive intermediates, lowering activation barriers\nof rate- and selectivity-determining steps. Here, we elucidate periodic\ntrends in metal surface oxidation resulting from interaction with\nnitric oxide and subsequent adsorbate reaction chemistry across the\nlate 3d transition-metal series with surface-sensitive ambient-pressure\nX-ray photoelectron spectroscopy (AP-XPS) and density functional theory\ncalculations. Metals with open d-shell orbitals (e.g., Fe, Co) favor\nstabilization of nitric oxide dissociation products (nitrogen adatoms,\nN*), while metals having near (e.g., Ni) or completely (e.g., Cu)\nclosed d shells promote nitric oxide oxidation toward nitrite and\nlower total nitrogen and N* coverage. Adsorbate core-level (O 1s and\nN 1s) binding energies capture electron localization around nitrogen,\nand eventually oxygen, as nitric oxide moves toward dissociation.\nMetal-nitride covalency increases with decreasing transition metal\nelectronegativity, where nitrogen adatom binding energies decrease\nas the transition metal d-band is pushed toward the Fermi level. This\nwork illustrates experimental and theoretical relationships between\nthe nature of the d-band in facilitating nitric oxide adsorption and\ndissociation chemistry, furthering fundamental understanding of the\nrole of metal electronic structure in determining catalytically relevant\nadsorption properties.